Among a variety of paints on golf balls, a polyurethane paint of the two-part curing type wherein polyol and polyisocyanate are mixed immediately before use is commonly adopted since it is resistant to substantial deformation, impact and friction.
As it is currently desired to increase the spin rate of golf balls, the cover has been made softer. In order to avoid any deformation of the soft cover during paint coat drying, it is now necessary to dry paint coats at lower temperatures. From the productivity standpoint, it is desired to reduce the curing time of paint in order that a series of coating steps from application to drying be finished in a short time.
One practice for improving the workability of paint (for example, low-temperature drying and time reduction) is to increase the amount of curing catalyst relative to the paint base. This is successful in promoting the curing reaction of the paint, but at the same time, reduces the pot life of the paint, inviting many drawbacks such as inefficient working and deterioration of the paint prior to application.
It is, therefore, desired to have a paint which has a satisfactory pot life and a short curing time and is thus improved in workability, and at the same time, forms a coat having improved characteristics including durability, water resistance and adhesion.